On Mon, Mar 14, 2016 at 11:04 AM, Linus Torvalds <torva...@linux-foundation.org> wrote: > > None of this insane complicated crap that buys us exactly *nothing*, > and depends on fancy new exception handling support etc etc.
Actually, the one _new_ thing we could do is to instead of removing the old crappy rdmsr()/wrmsr() implementation entirely, we'll just rename it to "rd/wrmsr_unsafe()", and not have any exception table stuff for that at all (so now you *will* get an oops and panic if you use that). The only reason to do that is for performance-critical MSR's that really don't want any overhead. Sure, they could just be changed to use "wrmsr_safe()", but for things like the APIC accesses, or update_debugctlmsr() (that is supposed to check for processor version) that can be truly critical, an explicitly _unsafe_ version may be the right thing to do. The fact is, the problem with rd/wrmsr is that we just did the defaults the wrong way around. Making the simple and obvious version be unsafe is just wrong. Linus _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel